With the increasing horsepower of modern tractors and the constant pressures of agricultural efficiencies, agricultural implements such as plows, rakes, harrows, disks, planters and the like have been increasing in their lateral dimensions. With the increased horsepower of the pulling implement of the tractor, more rows in a field can be cultivated simultaneously. Unfortunately, agricultural fields are uneven. As the implements increase in their lateral dimensions they do not follow the changing contours of the ground as accurately, leading to over- or under-penetration by ground-cultivating devices attached to the implement. For this reason in recent years the implements have been designed in several sections disposed along a line perpendicular to the direction of travel and connected to each other through generally flexible couplings disposed between the sections. The flexible couplings allow small upward or downward deflections between the sections of the implement as it travels over the ground, thus permitting each section to follow the contours of the field more accurately, and providing more even ground penetration by the attached devices.
There has been a trend in recent years to plant crops in rows spaced ever more closely together. As a result, each of the ground-cultivating devices such as row units for planting seed are spaced closer together on each section of the implement's tool bar. Given row spacings of fifteen inches, for example, the row units on a planter would be spaced fifteen inches apart, thereby providing a gap of only one to two inches between adjacent row units on adjacent sections of the tool bar. If such a coupling is used, there is a real danger that as one section of the tool bar is flexed upward or downward over a ground contour that it will cause adjacent row units to contact each other and break. What is needed, therefore, is an improved agricultural implement that will permit greater relative motion between adjacent sections of the implement while reducing the risk of damaging ground cultivating devices, such as row units, mounted on those sections. It is an object of this invention to provide such an implement